Two Sum using Unordered Map

Medium STL Containers

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Problem Statement

Write a C++ program using `std::unordered_map` to find indices of two numbers in an array that add up to a target sum.

Input Format

First line: N and Target. Second line: N space-separated integers.

Output Format

Print the two indices separated by a space.

Constraints

2 <= N <= 1000

Sample Input

4 9
2 7 11 15

Sample Output

0 1

Explanation

Hash maps achieve $O(N)$ time complexity for the Two Sum problem.

Starter Code

#include <iostream>
#include <unordered_map>
#include <vector>

int main() {
    int n, target;
    if (std::cin >> n >> target) {
        // Write your Two Sum hash map logic here

    }
    return 0;
}

Limits

Time Limit: 1s
Memory Limit: 256MB

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